Born in Glasgow, he trained as an architect with
H & D Barclay
, becoming their chief assistant.
In 1896, he became an assistant to
A B McDonald
in the City Engineerís office, and worked for Glasgow Corporation for the rest of his career.
As well as assisting in the design of many of the Corporationís buildings and public works, he was responsible for designing the combined Kingston Public Halls, Public Library and Police Office, 330-46 Paisley Road, which features an extensive scheme of figurative and portrait sculpture by
This includes a full-length allegorical statue representing Literature, a fine relief of the Glasgow Arms, and portrait reliefs of prominent politicians (the latter added in 1907).
Another of his projects in 1904 was the remodelling of the historic Ship Bank tenement in the Saltmarket.
A pioneering housing expert, he was responsible for designing the houses and layout for the garden suburbs of Riddrie and Mosspark (1913-27).
Horn became Chief Architect of Glasgow Corporationís Housing Department in 1919, its Assistant Director in 1923, and eventually its Director in 1928.
in 1895, he died on 4th January 1932.